Liquid Ejection Head Electrode Dummy Extended Portion Design
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Solution Overview
Problem
In liquid ejection heads with piezoelectric actuators, misalignment of individual electrodes can lead to varying volume decrease rates among active portions, resulting in inconsistent ink ejection properties and deteriorated recording quality, especially when electrodes have extended portions in opposite directions.
Innovation Solution
The liquid ejection head incorporates a design with a channel unit and actuator unit featuring a piezoelectric layer, individual electrodes with main and extended portions, and dummy extended portions that extend in opposite directions, ensuring uniform volume change and minimizing structural cross-talk, thus maintaining recording quality even with misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If extended portions of individual electrodes extend in opposite directions, then manufacturing workability is improved, but volume decrease rates of active portions vary significantly due to misalignment, deteriorating ink ejection properties
Solution Approach 1:
The patent applies local quality by making the extended portions have different lengths depending on their position and alignment status. Specifically, when misalignment is detected, the extended portion length is adjusted locally to compensate for the volume decrease, ensuring uniform ink ejection properties across all electrodes while maintaining the opposite-direction extension structure for manufacturing ease.
2Ease of manufacture
If individual electrodes are formed at the same time for workability, then manufacturing process is simplified, but misalignment causes different volume reduction rates among electrodes with extended portions in opposite directions
Solution Approach 1:
The patent applies preliminary action by pre-designing the extended portions with specific length characteristics that compensate for expected misalignment. The extended portions are formed with lengths calculated in advance to offset potential volume decreases, ensuring that even when electrodes are formed simultaneously and misalignment occurs, the ink ejection properties remain consistent across all electrodes.
3Manufacturing precision
If extended portions extend in opposite directions to compensate for misalignment, then volume reduction is minimized, but structural cross-talk increases
Solution Approach 1:
The patent applies parameter changes by adjusting the length parameter of extended portions based on their position and alignment status. When misalignment is detected, the extended portion length is specifically modified to compensate for volume decrease while controlling the degree of cross-talk. This parameter adjustment ensures optimal balance between volume compensation and harmful cross-talk prevention.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design prevents significant variations in active portion volume changes due to misalignment, maintaining consistent ink ejection properties and preventing structural cross-talk, thereby ensuring high-quality recording.
Implementation Method 1
an active portion (i.e., a portion of the piezoelectric layer which is sandwiched between the individual electrode and another electrode) is displaced. As a result, a volume of a pressure chamber facing the individual electrode is changed
Data Source
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AI summary
A liquid ejection head (10) including: a channel unit (12) having a plurality of pressure chambers (16), a plurality of ejection openings (14a), and a plurality of liquid channels (14) formed therein, the liquid channels respectively extending from the pressure chambers to the ejection openings; and an actuator unit (17) including a piezoelectric layer (17a) and a plurality of individual electrodes (18) formed on a face of the piezoelectric layer, the actuator unit being configured to apply a drive voltage to the individual electrodes to change volumes of the respective pressure chambers respectively corresponding to the individual electrodes, wherein each of the individual electrodes includes: a land (18c) to which the drive voltage is applied; a main portion (18a) disposed such that an entire area thereof is opposite to a corresponding one of the pressure chambers in a direction perpendicular to the face of the piezoelectric layer; an extended portion (18b1) extending, in an extending direction in which the extended portion extends, from the main portion toward the land along the face of the piezoelectric layer so as to connect the main portion and the land to each other; and a dummy extended portion (18b2) extending from the main portion along the face of the piezoelectric layer in an opposite direction opposite to the extending direction.